Battery charger



FIG. 1 is a front, elevational view of a battery charger showing our new design;

FIG. 2 is a rear, elevational view thereof;

FIG. 3 is a top, plan view thereof;

FIG. 4 is a bottom, plan view thereof;

FIG. 5 is a front, right, top, isometric view thereof; and,

FIG. 6 is a left, elevational view thereof.

The dashed lines indicate unclaimed subject matter by outline. 

The ornamental design for a battery charger, as shown and described. 